A person does not just consist of himself or herself, but also moves around with a collection of inanimate objects (e.g., a wallet, purse, keys, laptop, luggage, etc.) and also, at times, animate objects for which they are responsible (e.g., dependent children/adults, pets etc.). Keeping track of all these items and getting them from one place to another can, at times, be an overwhelming task, particularly in the distracted world that we live in.
Some representative examples include: every weekday morning from 7 am-9 am, a person going to work needs to leave the house with keys and a computer, and that same person, later leaving work at night, needs to have the same keys and computer to bring home; a parent, every school day, needs to leave the house with the child and all the child's school supplies; a technician going to a job site needs to have all the tools in his or her tool case; a surgeon, before commencing surgery, needs certain medical instruments present; a person checking out of a hotel room does not want to leave any items behind; and a person exiting a taxi does not want to forget his or her wallet.
However, not only is it difficult to track routine occurrences, but people are particularly prone to forget things while in unfamiliar situations, such as, for example, while traveling on vacation or on a business trip. In this case, the situation can be catastrophic, and not easily recoverable, since it might not be possible to simply return to pick up the missing item, because of distance or it may have been left in a public location, which means someone may take it.